Method of operating a document feeding mechanism to reduce chance of a document jam condition and an apparatus therefor

ABSTRACT

A method is provided of operating a document feeding mechanism having a document transport path which passes through an extended nip defined between an advance belt disposed on one side of a document transport path and a retard belt disposed on an opposite side of the document transport path. The method comprises controlling operation of the advance belt to pick sheets from a document stack and to feed picked sheets one-by-one through the extended nip from an upstream end of the document transport path to a downstream end of the document transport path, and controlling operation of the retard belt to hold back other sheets of the document stack from being fed through the extended nip as one sheet is being picked from the document stack and fed through the extended nip from the upstream end of the document transport path to the downstream end of the document transport path and thereby to reduce chance of a document jam condition.

BACKGROUND

The present invention relates to document feeding along a documenttransport path, and is particularly directed to a method of operating adocument feeding mechanism to reduce chance of a document jam conditionand an apparatus therefor.

A known type of document feeding mechanism 10 is illustrated in FIG. 1.The mechanism 10 includes an advance drive roller 12 which lies on oneside of a document transport path 14. The advance drive roller 12 isdriven to rotate about its longitudinal central axis to drive an advancebelt 16. The advance belt 16 picks sheets of documents from a documentstack 18, and feeds the sheets one-by-one along the document transportpath 14. Typically, the advance belt 16 has a high coefficient offriction to pull sheets off the top of the document stack 18.

The mechanism 10 further includes a retard drive roller 20 which lies onthe opposite side of the document transport path 14 and faces theadvance drive roller 12 to form a nip 22 therebetween. The retard driveroller 20 is driven to rotate about its longitudinal central axis sothat it is counter rotating relative to the advance drive roller 12 inthe nip 22. The counter rotation of the retard drive roller 20 acts tohold back other sheets when a single sheet is being fed through the nip22 along the document transport path 14.

A drawback in using the known document feeding mechanism 10 of FIG. 1 isthat a very limp or soft sheet 30 (such as a used banknote for example)may fold over at the separation point, such as shown FIG. 2, when thesheet is being separated away from the document stack 18. This foldingover of the limp sheet 30 may cause a document jam condition to occuralong the document transport path 14. If the folding over of the limpsheet 30 rolls along the sheet, such as shown in FIG. 3, the sheet mayeven flip over. It would be desirable to provide a document feedingmechanism in which a very limp or soft sheet can be fed through the nip22 along the document transport path 14 with reduced chance of the sheeteither flipping over or causing a document jam condition.

SUMMARY

In accordance with one embodiment of the present invention, a method isprovided of operating a document feeding mechanism having a documenttransport path which passes through an extended nip defined between anadvance belt disposed on one side of a document transport path and aretard belt disposed on an opposite side of the document transport path.The method comprises controlling operation of the advance belt to picksheets from a document stack and to feed picked sheets one-by-onethrough the extended nip from an upstream end of the document transportpath to a downstream end of the document transport path, and controllingoperation of the retard belt to hold back other sheets of the documentstack from being fed through the extended nip as one sheet is beingpicked from the document stack and fed through the extended nip from theupstream end of the document transport path to the downstream end of thedocument transport path and thereby to reduce chance of a document jamcondition.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings:

FIGS. 1-3 is a schematic view of a known document feeding mechanism;

FIG. 4 is a schematic view of a document feeding mechanism constructedin accordance with one embodiment of the present invention;

FIGS. 5 and 6 are views similar to FIG. 4 and showing parts in differentpositions.

DETAILED DESCRIPTION

The present invention is directed to a method of operating a documentfeeding mechanism to reduce chance of a document jam condition and anapparatus therefor. The specific use and construction of the documentfeeding mechanism may vary. By way of example, a document feedingmechanism 50 constructed in accordance with one embodiment of thepresent invention is illustrated in FIG. 4.

The document feeding mechanism 50 has an upstream end 52, a downstreamend 54, and a document transport path 56 extending between the upstreamend and the downstream end. The document feeding mechanism 50 includesan advance drive roller 60 which is adjacent to one side of the documenttransport path 56. The advance drive roller 60 has a longitudinalcentral axis and an outer circumferential surface 62. The advance driveroller 60 is rotatably mounted on a first shaft 64 for rotation aboutits longitudinal central axis.

The document feeding mechanism 50 further includes a retard drive roller70 which is adjacent to an opposite side of the document transport path56 and faces the advance drive roller 60. The retard drive roller 70 hasa longitudinal central axis and an outer circumferential surface 72. Theretard drive roller 70 is rotatably mounted on a second shaft 74 forrotation about its longitudinal central axis. A nip 58 is definedbetween the outer circumferential surface 62 of the advance drive roller60 and the outer circumferential surface 72 of the retard drive roller70.

The document feeding mechanism 50 also includes a first endlesscontinuous belt 80 which is drivingly coupled between the advance driveroller 60 and a first idler roller 66, and a second endless continuousbelt 90 which is drivingly coupled between the retard drive roller 70and a second idler roller 76. The first belt 80 is referred to herein asthe “advance belt”, and the second belt 90 is referred to herein as the“retard belt”. The first belt 80 has an outer circumferential surface82, and the second belt 90 has an outer circumferential surface 92. Anextended nip 88 is defined between the outer circumferential surface 82of the first belt 80 and the outer circumferential surface 92 of thesecond belt 90.

As shown in FIG. 4, the extended nip 88 is disposed along the documenttransport path 56 approximately between the longitudinal central axis ofthe second idler roller 76 and the longitudinal central axis of theretard drive roller 70. The extended nip 88 overlies the relativelysmaller nip 58, and is disposed over a linear portion of the documenttransport path 56. Accordingly, the document transport path 56 passesthrough both the nip 58 and the extended nip 88.

A controller 100 provides a control signal via line 102 to the advancedrive roller 60 to control operation of the advance drive roller andthereby to control operation of the advance belt 80. The controller 100also provides a control signal via line 104 to the retard drive roller70 to control operation of the retard drive roller and thereby tocontrol operation of the retard belt 90.

During operation of the document feeding mechanism 50 (as shown in FIG.4), the controller 100 controls the advance drive roller 60 to rotateabout its longitudinal central axis in the counter-clockwise direction(as viewed looking at FIG. 4). The controller 100 controls the retarddrive roller 60 to rotate about its longitudinal central axis also inthe counter-clockwise direction. As the advance drive roller 60 and theretard drive roller 70 both rotate in the counter-clockwise direction,the advance and retard belts 80, 90 co-operate to pick and feed a singledocument 110 from a document stack 108 through the extended nip 88 alongthe document transport path 56.

More specifically, due to frictional engagement of the outercircumferential surface 82 of the advance belt 80 with the singledocument 110, the leading edge 112 of the document 110 is transportedfrom the position shown FIG. 4 to the position shown in FIG. 5. In FIG.5, the leading edge 112 of the document 110 is shown positioned betweenthe outer circumferential surface 82 of the advance belt 80 and theouter circumferential surface 92 of the retard belt 90. As the document110 continues to move downstream along the document transport path 56from the position shown in FIG. 5 to the position shown in FIG. 6, theleading edge 112 of the document 110 exits the extended nip 88. Thedocument 110 continues to move downstream along the document transportpath 56 for further handling and processing at the downstream end of thedocument transport path.

It should be apparent that the operation of the document feedingmechanism 50 described hereinabove enables the document 110 to be fedthrough the relatively larger extended nip 88 which is defined betweenthe advance and retard belts 80, 90 instead of being fed through justthe relatively smaller nip 88 which is defined between the advance driveroller 60 and the retard drive roller 70. By feeding the document 110through the linearly-extending nip 88, the tendency of the leading edge112 of the document 110 to fold over, and thereby possibly causing adocument jam condition, is reduced. The tendency of such a fold to rollalong the length of the document 110, and thereby possibly causing thedocument to flip over, is also reduced.

The particular arrangements disclosed are meant to be illustrative onlyand not limiting as to the scope of the invention. From the abovedescription, those skilled in the art to which the present inventionrelates will perceive improvements, changes and modifications. Numeroussubstitutions and modifications can be undertaken without departing fromthe true spirit and scope of the invention. Such improvements, changesand modifications within the skill of the art to which the presentinvention relates are intended to be covered by the appended claims.

1. A method of operating a document feeding mechanism having a documenttransport path which passes through an extended nip defined between anadvance belt disposed on one side of a document transport path and aretard belt disposed on an opposite side of the document transport path,the method comprising: controlling operation of the advance belt to picksheets from a document stack and to feed picked sheets one-by-onethrough the extended nip from an upstream end of the document transportpath to a downstream end of the document transport path; and controllingoperation of the retard belt to (i) hold back other sheets of thedocument stack from being fed through the extended nip as one sheet isbeing picked from the document stack and fed through the extended nipfrom the upstream end of the document transport path to the downstreamend of the document transport path, and (ii) reduce tendency of aleading edge of the one sheet to fold over and roll along its length asthe leading edge is being fed into the extended nip and thereby toreduce chance of a document jam condition.
 2. A method according toclaim 1, wherein the extended nip is disposed along a linear portion ofthe document transport path.
 3. A method according to claim 2, whereinthe extended nip overlies a relatively smaller nip which is disposedbetween an advance drive roller driving the advance belt and a retarddrive roller driving the retard belt. 4-9. (canceled)
 10. A method ofoperating a banknote feeding mechanism having a banknote transport pathwhich passes through an extended nip defined between an advance beltdisposed on one side of the banknote transport path and a retard beltdisposed on an opposite side of the banknote transport path, the methodcomprising: locating the retard belt relative to a stack of usedbanknotes to enable the retard belt to reduce tendency of a leading edgeof a used banknote which has been picked from the stack to fold over androll along its length as the leading edge is being fed into the extendednip and thereby to reduce chance of a banknote jam condition along thebanknote transport path.
 11. A method according to claim 10, wherein theextended nip is disposed along a linear portion of the banknotetransport path.
 12. A method according to claim 11, wherein the extendednip overlies a relatively smaller nip which is disposed between anadvance drive roller driving the advance belt and a retard drive rollerdriving the retard belt.
 13. A method of operating a banknote feedingmechanism having a banknote transport path which passes through anextended nip defined between an advance belt disposed on one side of thebanknote transport path and a retard belt disposed on an opposite sideof the banknote transport path, the method comprising: locating theadvance belt relative to a stack of limp, used banknotes to pick limp,used banknotes from the stack and to feed limp, used banknotesone-by-one through the extended nip from an upstream end of the banknotetransport path to a downstream end of the banknote transport path; andlocating the retard belt relative to the advance belt and the stack oflimp, used banknotes to enable the retard belt to reduce tendency of aleading edge of a limp, used banknote which has been picked from thestack to fold over and roll along its length as the leading edge isbeing fed into the extended nip and thereby to reduce chance of abanknote jam condition along the banknote transport path.
 14. A methodaccording to claim 13, wherein the extended nip is disposed along alinear portion of the banknote transport path.
 15. A method according toclaim 14, wherein the extended nip overlies a relatively smaller nipwhich is disposed between an advance drive roller driving the advancebelt and a retard drive roller driving the retard belt.